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baritone
Starting Member
USA
7 Posts |
 Posted - 03/10/2006 : 10:15:08 AM
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My neighborhood (Lower Manhattan) was wired when Edison hadn't yet reached middle age. My house, like many around here, has single-phase service, split into two legs to provide 220v. I just spoke with Smarthome technical support to discuss the implications of this setup for Insteon. The answer was clear and concise, to wit: There is no difference between split-single-phase and two-phase. They are synonyms. The service rep. verified her answer with a colleague.
I'm not an EE, but to me this sounds fishy. I believe split-single-phase to mean that the sine waves in two legs of circuitry coincide, and that two-phase means that the respective sine waves are offset.
Can someone answer the following questions?
1. Are split-single-phase and two-phase synonymous?
2. If not, is my description of the difference between the two correct?
3. Will Insteon work equally well on split-single-phase and two-phase installations?
4. What differences in Insteon setup or behavior should I expect?
5. Specifically, by what method do a pair of RF signal enhancers (2442) determine "successful synchronization" (rapid blinking) during setup?
6. REALLY specifically, does the rapid blink indicate that the two 2442's have detected that they are receiving power in different phases?
7. QED punchline: Will I ever see the coveted rapid blinking when I install 2442's in my split-single-phase-wired house?
Sorry to be long-winded. Thanks to all. |
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jhimmel
Average Member
114 Posts |
Posted - 03/10/2006 : 2:40:08 PM
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Split single phase is the more acurate description of what most of us have in our homes and it is what Insteon was designed for. You have no worries.
Jim H. |
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mike
Advanced Member
USA
1131 Posts |
Posted - 03/10/2006 : 3:48:42 PM
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baritone -
Jhimmel is correct. Split-single phase power is the most common type of power delivered today by the power company (regardless of when the wires were laid). In either case where the two legs of electricity are on the same polarity or opposite (most common), INSTEON will work normally and not behave any different. If the house has 220v appliances, then that house is wired with split single phase service and the two SignaLinc RF's would be needed to bridge the phases. |
SmartLabsMike
INSTEON - Linking Everything to Everything Else.
http://www.insteon.net |
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baritone
Starting Member
USA
7 Posts |
Posted - 03/11/2006 : 10:09:46 AM
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Excellent. I apologize to Smarthome's phone techs. This also gives me the opportunity to praise one aspect of the 800 number's service: the system let me leave a callback number instead of waiting on the queue. The tech rep called promptly. Why doesn't every business offer this service? Better than a drug, for lowering blood pressure.
Mike, to satisfy my curiosity, can you answer one of my previous questions:
5. Specifically, by what method do a pair of RF signal enhancers (2442) determine "successful synchronization" (rapid blinking) during setup?
So far I've achieved only the slow blink. I'm fairly certain that the two 2442's are on opposite legs, based on inspection of the circuit-breaker box wiring.
Thanks. |
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jhimmel
Average Member
114 Posts |
Posted - 03/11/2006 : 10:22:26 AM
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Are you sure?
A typical circuit-breaker box will alternate phases as they go down the vertical rows. So, as you look down either the left row or the right row of breakers, each one as you go down the row will be on the alternate phase - except where double breakers are fit into single slots.
Is that clear? Take the left row of breakers -
Number one is phase one, number two is phase two, number three is phase one, number four is phase two.
I suggest you keep trying outlets further to try and get the Signalincs to sync.
Jim H. |
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Buddha
Average Member
84 Posts |
Posted - 03/11/2006 : 10:30:25 AM
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baritone,
i think jhimmel is right, i'd keep trying outlets
in some homes most outlets are on one phase and most switches/dimmers are on the other so it may take many attempts to find outlets on both "phases" (even though they are truly split-single of same phase)
good luck
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baritone
Starting Member
USA
7 Posts |
Posted - 03/11/2006 : 10:43:11 AM
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| I tested according to the plan you specify, Jim. In particular I tested using the pair of circuits whose breakers (consecutive in the left column) are directly opposite a pair of breakers ganged together in the right column; the latter pair supplies power to the central AC. |
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Buddha
Average Member
84 Posts |
Posted - 03/11/2006 : 12:00:38 PM
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bariton,
what did you find? did you find alternating phases? or not?
his advice is correct in general, but not necessarily always (every electrician can do it differently)....
hope you found locations for your two signalincs.....remember, you only need the two signalincs installed if you are having problems......
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baritone
Starting Member
USA
7 Posts |
Posted - 03/11/2006 : 12:23:47 PM
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Buddha,
I get slow blink only in the 2442's installed in opposite legs. I'm still reluctant to call them opposite "phases." I haven't installed any additional Insteon hardware, but based on my previous X10 experience I expect that I'll need the cross-leg communication boost. I'll install a couple of switches and a wall controller tomorrow. |
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jhimmel
Average Member
114 Posts |
Posted - 03/11/2006 : 2:46:26 PM
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quote:
Originally posted by baritone
I tested according to the plan you specify, Jim. In particular I tested using the pair of circuits whose breakers (consecutive in the left column) are directly opposite a pair of breakers ganged together in the right column; the latter pair supplies power to the central AC.
If you follwed the output of those circuits carefully and you are sure the signalincs are plugged into those circuits, you should be on two seperate legs. The pair that are ganged together directly oposite them (your AC) is a 220 circuit, and demonstrates to me that your panel is set up as I described.
Jim H. |
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baritone
Starting Member
USA
7 Posts |
Posted - 03/12/2006 : 09:01:00 AM
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| Oy. I had it backwards. Let me try again. Please forgive (and correct) sloppiness or inaccuracies; remember, I’m not an EE.
As the respondents in this thread said, most residences in the U.S. have “three-wire split-single-phase” service: two hot feeds, each supplying 120 volts, and a neutral. The AC oscillations of the two phases coincide. Using two legs together yields 240 volts; thus this is known also as “120/240” service.
Commercial service often requires “four-wire three-phase” service. Each of the three 120 volt AC phases is offset from the others by 120 degrees. Because commercial power needs in New York City dwarf residential needs, three-phase wiring is standard. Customers who do not need three-phase are supplied two of the three feeds, plus a neutral; i.e., “three-wire two-phase” service. AC phases in the two legs are offset by 120 degrees. Using both legs together produces a smaller-amplitude sine wave than does combining two same-phase feeds, and 208 volts, not 240—because the peaks of the 120-volt sine waves do not coincide. This type of service is therefore known also as “120/208” service.
I tested this at home using a voltage meter. It sensed 123.8 volts in one leg and 122.5 in the other. Across the two hot feeds, the voltage was 213.4, close to the expected value for two-phase, (sum * sqrt(3)).
A note on terminology: while “two-phase” is popularly used as a synonym for “split-single-phase,” this usage, according to Wikipedia ( http://en.wikipedia.org/wiki/Single-phase_electric_power ) is inaccurate. Most of you reading this have split-single-phase. I have two-phase—unfortunately, I think.
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Buddha
Average Member
84 Posts |
Posted - 03/12/2006 : 09:35:29 AM
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As I undertsand it, the 3-phase challenges for INSTEON are all timing related. I don't believe any of these issues would exist for a true, two phase installation -- should that in fact be your situation. Have you installed and tested any devices yet? Would be interested to hear how it goes.
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baritone
Starting Member
USA
7 Posts |
Posted - 03/12/2006 : 1:08:08 PM
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Timing seems indeed to be the problem. From what I can tell, Insteon transmits and receives signals only in an interval that includes the sine wave's zero crossing. X10 listens and transmits at this point also, but (at least in some devices) repeats the transmission at the points where phases 120 degrees out of sync would be listening.
I tested. First the RF SignaLinks: I was able to get a pair of them to sync with the rapid blink. They were on circuits on opposite legs, but installed on the same floor. I tried more possibilities, but couldn't get this behavior if they were on different floors. I always saw the slow blink, but completed the link procedure anyway.
Now the dimmers: I wired an Insteon "paddle" dimmer (2476D) to control a lamp, and a keypad dimmer (2486D) to control nothing. I wired them to 3-prong plugs so I could test various circuit combinations. For each test I attempted to cross-link the two devices. I did a factory reset on both before each test. The results:
Both devices on the same circuit: Success. The cross-link worked. The keypad controlled the lamp, and its button light changed appropriately when I used the paddle dimmer.
Separate circuits, same leg: NG. Attempts at linking left both devices blinking--the LED on the paddle dimmer and the button on the keypad. Neither device affected the other. This happened whether or not the SignaLinks were plugged into these circuits.
Circuits on opposite legs: NG; same failure. Again installing SignalLinks on these circuits didn't improve matters, even when they had blinked fast during setup.
Now the weird part: If the SignaLinks were happy--circuits on separate legs, SignaLinks on the same floor--the dim/bright function on the keypad controlled the light, but on/off did not. (Maybe dim/bright sends a continuous signal via RF?) What's more, this behavior persisted after I unplugged and factory-reset both devices. I was able to see it only because I had, in the previous test, successfully linked the two dimmers when they were plugged into the same circuit.
I still hope for a solution. (Perhaps a device that propagates the Insteon signal at 120-degree offsets?) Meanwhile, I guess it's back to X10 (gag) . . .
Thanks again, group. Good luck to all. |
Edited by - baritone on 03/12/2006 3:07:26 PM |
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jhimmel
Average Member
114 Posts |
Posted - 03/12/2006 : 2:09:23 PM
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That is a shame, baritone.
I hope Insteon can address this some day.
Take care.
Jim H. |
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dhouston
Average Member
135 Posts |
Posted - 04/07/2006 : 06:00:23 AM
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quote:
Originally posted by mike
Split-single phase power is the most common type of power delivered today by the power company (regardless of when the wires were laid). In either case where the two legs of electricity are on the same polarity or opposite (most common), INSTEON will work normally and not behave any different. If the house has 220v appliances, then that house is wired with split single phase service and the two SignaLinc RF's would be needed to bridge the phases.
Split-phase, splits one 240V phase into two 120V phases that are 180° out of phase. The zero crossings coincide except for polarity. The time between ZC is 8-1/3ms @ 60Hz.
Three-phase has phases that are 120° apart. The zero crossings do not coincide. The times between ZC of the various phases is 6-1/4ms @ 60Hz.
Insteon couples the phases using RF during one half-cycle (8-1/3ms) of the powerline. I'm not sure it has time to couple the phases and sync transmissions when it must do it in 6-1/4ms. I don't think extended codes can fit within that timeframe.
True two-phase (rare) has phases at 90° which only gives 4-1/6ms between ZC from one phase to the other. |
Edited by - dhouston on 04/07/2006 06:14:17 AM |
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Buddha
Average Member
84 Posts |
Posted - 04/08/2006 : 12:35:06 PM
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I have had the opportunity to do some testing on 3-phase installations and am finding that my INSTEON installs are working fine. Also, I believe the accurate description of split single phase is that it takes two phases (180 degrees out of synch from one another) and then adds them together to create 220V potential between the peak of "phase one" and the valley of "phase two"
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bmoraes
Starting Member
Brazil
14 Posts |
Posted - 01/23/2007 : 04:37:17 AM
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HI Buddha and others,
how did you manage to have the systems working on a 3-phase environment? I'm having several problems to make the INSTEON modules to communicate.
Thanks, Bruno |
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Topic |
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Split-single-phase v. two-phase
